Blister packs are well know in the art and are widely used to package individual items such as different forms of medication including tablets, capsules and the like. In addition, the packaging of a small amount of liquid in an individual blister is known.
Usually, the item or product is accessed through the rear of the blister pack which is provided with a tear strip.
As aforementioned, there are three different properties which any packaging ideally possesses. The first is that the package should be tamper evident such that there will be provided a clear indication when the package has been subject to tampering. A second feature is that the package be child resistant. As aforementioned, such packages are frequently used for medication and it is inherently desirable that one prevents young children from accessing the contents of the blister pack.
However, in making such packaging child resistant, it is also important that the package still be readily openable by those taking the medication. Since the most frequent users of medication are seniors, one must take into account the limits of their ability when they are suffering from various physical problems.
A conventional blister package usually comprises a laminate of a blister layer having article receiving pockets formed therein and with the article receiving pockets being covered by a foil backing layer. This foil backing layer is usually a form of an aluminum foil which is rupturable to permit access to the product in the blister pocket. While such a package is inherently tamper evident unless the whole foil layer is replaced, it is not very child resistant and indeed can prove attractive to some children.
To overcome this, there has been suggestions in the art, such as shown in U.S. Pat. No. 4,537,312 to Intini, to include such certain child resistant features. In the arrangement of Intini, there is provided a blister package having a front layer and outer back layer which are sized larger than the conventional package and sealed to one another around their periphery and through apertures in the laminate. Tabs are provided at the edges of the sealed front and back layers and which tabs are connected to tear strips in the back layer, each of which overlays the foil covering a blister pocket. On removing the tear strips in the back layer, there will be left a layer or stratum of paperboard which overlays the foil to thereby reinforce it and make it more difficult for the child to access the product in the blister pocket.
A further feature which must always be considered in designing such products is the ability to efficiently manufacture the package at a reasonable cost. It is also highly desirable that the results be reproducible.